1. Field of the Invention
The present invention relates to a hydrodynamic coupling device, in particular a hydrodynamic torque converter or fluid clutch, comprising a housing which is, or can be, filled with hydraulic fluid, a turbine wheel which is rotatably arranged in the housing and is, or can be, connected to an output shaft for joint rotation, and a sliding bearing arrangement by means of which the turbine wheel is rotatably mounted relative to the housing, and which has a hydraulic fluid channel arrangement for the passage of hydraulic fluid from radially outside to radially inside relative to the region of the output shaft, or vice versa.
2. Description of the Related Art
Such a hydrodynamic coupling device in the form of a hydrodynamic torque converter is known from DE 44 23 640 A1. A critical region of such hydrodynamic coupling devices is that region in which, for example, hydraulic fluid flowing up from radially outside must be led to leave the interior of the housing into the central region in which it can then be removed via an axial passage opening, for example in the output shaft. It must be ensured in this region, on the one hand, that a suitable bearing or support of the turbine wheel or of the free end of the output shaft, in general a transmission input shaft, is provided relative to the housing, but that, the hydraulic fluid can flow into this radially inner region without eddies being produced in rotary operation. For this purpose, it is known, for example, to weld into a housing cover as a central part thereof a bearing element which has bores for the passage of oil which lead radially inward, the support by means of a rolling-element bearing also being performed simultaneously at this component. It is also known to use bearings, for example sliding bearings, supported axially on the housing, on the one hand, and on the turbine wheel, on the other hand, for suitable support, these bearings then having channel-like passage regions, in order to guide the fluid radially inward.
DE 199 09 349 A1 discloses a hydrodynamic coupling device in the form of a hydrodynamic torque converter in the case of which, ultimately, the output shaft and the turbine wheel coupled to the latter for joint rotation is not supported in the free end region of the output shaft relative to the housing. Furthermore, there is arranged on the housing a fluid flow guiding element which deflects the radially approaching hydraulic fluid into the axial passage opening of the output shaft.
It is the object of the present invention to develop a hydrodynamic coupling device of the generic type so as to permit the converter hydraulic fluid to flow radially in a fashion essentially uninfluenced by eddies in conjunction with a simple design.
In accordance with a first aspect of the present invention, this object is achieved by means of a hydrodynamic coupling device, in particular a hydrodynamic torque converter or fluid clutch, comprising a housing which is, or can be, filled with hydraulic fluid, a turbine wheel which is rotatably arranged in the housing and is, or can be, connected to an output shaft for joint rotation, and a sliding bearing arrangement by means of which the turbine wheel is rotatably mounted relative to the housing, and which has a hydraulic fluid channel arrangement for the passage of hydraulic fluid from radially outside to radially inside relative to the region of the output shaft, or vice versa.
It is further provided in accordance with the invention that the sliding bearing arrangement comprises a sliding bearing element fixed on the turbine wheel, and that the sliding bearing element supports the turbine wheel in the axial and radial directions relative to the housing.
In the case of such a coupling device, the sliding bearing element ensures a suitable axial and radial support, it being possible to carry out the operation of assembly in a simplified fashion because this sliding bearing element is fixed on the turbine wheel. The sliding bearing element nevertheless permits the hydraulic fluid to pass via the hydraulic fluid channel arrangement, so that it is possible to dispense with separate modules therefor.
The design of the device according to the invention can be simplified by virtue of the fact that the sliding bearing element is supported on an inner surface of the housing with a surface region facing the housing. It is particularly advantageous in this case for reasons of production engineering when at least one, preferably a plurality of, groove-like depression(s) is/are provided in the surface region for the purpose of providing the hydraulic fluid channel arrangement, the at least one groove-like depression being covered at least partially by the inner surface of the housing.
It can further be provided that the sliding bearing element has a fastening region with the aid of which said element is fixed on the turbine wheel, preferably a turbine wheel hub of the same. Here also, the design becomes simpler again when the fastening region is connected to the turbine wheel by being pressed in.
In order both to meet the requirements occurring in rotary operation and to be able to carry out the production as simply and cost-effectively as possible, it is proposed that the sliding bearing element is formed from plastic, preferably polyamide 6,6 (PA6,6), polyamide 4,6 (PA4,6) or polyether ketone (PEK), from sintered metal or aluminum.
In order to provide the bearing function addressed both in the axial and in the radial direction, it is proposed that the sliding bearing element has an axial bearing surface region extending essentially radially, and a radial bearing surface region extending essentially axially.
Alternatively, or in addition, it can be provided that the sliding bearing element has an axial/radial bearing surface region constructed in an essentially frustoconical fashion. A suitable centering of the two modules to be brought into rotary connection with one another is simultaneously achieved in this way.
In order, furthermore, to permit hydraulic fluid to approach from and to the axial passage opening, it is proposed that in its region near the axis of rotation, the sliding bearing element has a passage opening for connecting the hydraulic fluid channel arrangement to an axial passage opening constructed in the output shaft.
In the case of such hydrodynamic coupling devices, provision is generally made of a lockup clutch which, for the purpose of producing an essentially direct torque transmitting connection between the housing and the turbine wheel comprises an axially movable clutch element. In order to ensure in the case of such a variant embodiment with a lockup clutch that a tight seal is created relative to the housing in the region of the guidance of the clutch element in conjunction with axial mobility of the clutch element, it is proposed that provided on the housing in a fashion surrounding the sliding bearing element is a guide element on which a clutch element of a lockup clutch is guided such that it can be moved in the axial direction, that the guide element has a hydraulic fluid channel arrangement which is connected for fluid exchange to the hydraulic fluid channel arrangement in the sliding bearing element, and that the guide element is sealed off from the turbine wheel or/and the sliding bearing element in such a way that an exchange of hydraulic fluid is possible only via the two hydraulic fluid channel arrangements.
In accordance with a further aspect of the present invention, the object mentioned at the beginning is achieved by means of a hydrodynamic coupling device, in particular a hydrodynamic torque converter or fluid clutch, comprising a housing which is, or can be, filled with hydraulic fluid, a turbine wheel which is rotatably arranged in the housing and is, or can be, connected to an output shaft for joint rotation, and a bearing arrangement by means of which the turbine wheel is rotatably supported relative to the housing, and which has a hydraulic fluid channel arrangement for the passage of hydraulic fluid from radially outside to radially inside relative to the region of the output shaft, or vice versa, the bearing arrangement having a bearing which supports the turbine wheel axially and radially relative to the housing.
It is further provided in accordance with the invention that the bearing arrangement comprises a bearing element which is fixed on an inner surface of the housing and which has on its surface facing the inner surface of the housing at least one, preferably a plurality of, groove-like depression(s) which, for the purpose of providing the hydraulic fluid channel arrangement, is/are covered at least partially by the inner surface of the housing, and that the bearing is supported on the housing side on the bearing element.
The functioning of the hydraulic fluid guidance on the one hand, and the functioning of the axial or radial support of the turbine wheel relative to the housing on the other hand, can be provided in a very narrow spatial region in this way.
Given the use of a lockup clutch arrangement, it is preferred in this case that a clutch element of a lockup clutch arrangement is guided such that it can be moved axially on the bearing element. Thus, in the case of this embodiment the bearing element itself can also simultaneously take over the guidance of the clutch element.
It is preferably provided that the clutch element is connected in an essentially rotationally secure fashion to the bearing element. In order to ensure the passage of fluid from or to the axial passage opening in the output shaft in a fashion as free from disturbance as possible, it is further proposed that the bearing element is sealed off from the output shaft in its radially inner region.
In accordance with a further aspect of the present invention, the object named at the beginning is achieved by means of a hydrodynamic coupling device, in particular a hydrodynamic torque converter or fluid clutch, comprising a housing which is, or can be, filled with hydraulic fluid, a turbine wheel which is rotatably arranged in the housing and is, or can be, connected to an output shaft for joint rotation, a bearing arrangement by means of which the turbine wheel is supported axially and, if appropriate, radially relative to the housing, a hydraulic fluid channel arrangement, via which the passage of hydraulic fluid is possible from radially outside relative to the region of the output shaft, and vice versa.
It is provided in this case that the hydraulic fluid channel arrangement in a turbine wheel hub of the turbine wheel comprises at least one first passage opening extending essentially radially, and comprises in the output shaft at least one second passage opening which is connected to an axial passage opening of said shaft and extends essentially radially. This arrangement also ensures the axial and radial bearing of the turbine wheel relative to the housing, and the guidance of the hydraulic fluid in a region near the output shaft.
In order to permit a throughflow which is as free from disturbance as possible, it is advantageous in this case when the at least one first passage opening and the at least one second passage opening are situated in the same axial region.
It is advantageous, moreover, when the at least one first passage opening and the at least one second passage opening open into an interspace formed between the turbine wheel hub and the output shaft and preferably axially sealed off.
In accordance with a further aspect, the object mentioned at the beginning is achieved by means of a hydrodynamic coupling device, in particular a hydrodynamic torque converter or fluid clutch, comprising a housing which is, or can be, filled with hydraulic fluid, a turbine wheel which is rotatably arranged in the housing and is, or can be, connected to an output shaft for joint rotation, and a fluid guiding element which is provided on the housing and through which hydraulic fluid flowing up from radially outside is directed into an axial passage opening constructed in the output shaft, and vice versa.
This coupling device further has a bearing arrangement which is provided radially outside the fluid guiding element and by means of which the turbine wheel is supported axially and, if appropriate, radially relative to the housing.
It is possible in the case of this variant embodiment to obtain an assembly which is very easy to carry out by virtue of the fact that the fluid guiding element is pressed with a fastening section of the same into a depression in the housing.
For example, the bearing arrangement may comprise a sliding bearing or/and a rolling-element bearing.
In order to achieve a guidance of the hydraulic fluid which is essentially free from eddies in the radially inner region, it is proposed that the fluid guiding element has at least one, preferably a plurality of, groove-like fluid guiding depression(s) which is/are open on a side facing the output shaft.
The present invention is described below with reference to the attached drawings with the aid of preferred embodiments.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.